Investigation of structural and Electrical characteristics of some Lead free ferroelectrics

Abstract

Multi-functionalities of the ferroelectric materials have triggered the research to newlineunderstand the intriguing physics of materials and the development of tailor-made newlinematerials for potential technological applications. Despite the benefits and the success of newlinelead-based ferroelectric materials in electrical devices, there is a global concern about newlinethe adverse effect of lead on the environment and living organisms. It constitutes a newlineserious challenge to modern societies and there is an imminent need for coordinated newlineefforts by the material scientists for the fabrication of lead-free devices with an eye on newlinesustainable development. newlineBismuth layer structured ferroelectric compounds of the Aurivillius family show newlineinteresting physical properties and are of great interest due to their stronger anisotropic newlineelectrochemical coupling, higher stability, higher transition temperature, and higher newlineoperating frequency. The compounds have the potentiality to replace the lead-based newlinecompounds in the dielectric/ferroelectric industry. Bi3TiNbO9 (BTN) having m = 2 (TC = newline914°C), is found to be the most potential candidate and finds applications in the fields of newlineelectronics, power plants, aerospace, aeronautic and automotive industries. However, newlinethis compound possesses structural distortions and oxygen vacancies created by the newlineasymmetric Bi3+ cations. The compound is reported to have a dielectric constant of 170 newlineand tanand#948; of 0.3 at 500°C and 1 MHz. Thus, to improve upon the dielectric constant, we newlinehave considered replacing Nb5+ ion by V5+ because V5+ possesses the smallest ionic newlineradius among all the +5 oxidation state of the transition elements and provides greater newline rattling spaceand#8223; in the oxygen octahedral units to promote polarization. In that newlineprospective, Bi3TiVO9 (BTV) is the first/parent compound of the present research work, newlinefabricated by the solid-state reaction method. It has been found that with the replacement newlineof Nb5+ by V5+ at the B- site of BTN i.e. in BTV, the dielectric constant increases by newlinenearly 5 times to 872 at 500°C and 1